TW202214789A - Phosphor coating material, coating film, phosphor board and lighting apparatus - Google Patents

Abstract

A phosphor coating material containing phosphor particles and a curable resin component. In this phosphor coating material, the phosphor particle content within the entire nonvolatile component is at least 25 vol% but not more than 60vol%. This phosphor coating material can be used to produce a coating film (phosphor layer), a phosphor board, or a lighting apparatus or the like.

Description

Phosphor paint, coating film, phosphor substrate and lighting device

The present invention relates to a phosphor coating material, a coating film, a phosphor substrate and a lighting device.

Various developments have been made for lighting devices using LEDs (Light Emitting Devices). Not only the development of LEDs themselves, but also the development of mounting substrates with LEDs.

For example, in Example 2 of Patent Document 1, it is described that (i) a glass binder paint containing 30 vol% phosphor is applied on the surface of a glass substrate to form a phosphor layer with a thickness of 200 µm, (ii) here A mounting board for LED lighting is obtained by bonding a plurality of CSPs to a glass substrate, and (iii) when the mounting board is energized, light is emitted from the plurality of CSPs, and the problems of glare and multiple shadows can be reduced. [The so-called CSP is the abbreviation of Chip Scale Package or Chip Size Package (Chip Size Package). structure〕. [Prior Art Documents] [Patent Documents]

[Patent Document 1] International Publication No. 2019/093339

[Problems to be Solved by Invention]

In Example 2 of Patent Document 1, a phosphor layer with a thickness of 200 µm is formed on a glass substrate using a phosphor-containing "glass adhesive paint". However, since a sintering step at a high temperature is usually required to fully harden the glass adhesive coating, there is still room for improvement in the convenience of providing the phosphor layer. In addition, the case/substrate to which the glass adhesive coating is applied also has limitations in terms of heat resistance and optimization of the expansion coefficient.

The present invention has been developed in view of this situation. An object of the present invention is to provide a material that can easily form a phosphor layer. [How to solve the problem]

The inventors of the present application have completed the invention provided below through intensive research, and solved the above-mentioned problems.

According to the present invention, there is provided a phosphor coating material comprising phosphor particles and a curable resin component, and the content rate of the phosphor particles in all nonvolatile components is 25 vol % or more and 60 vol % or less.

Furthermore, according to the present invention, there is further provided a coating film formed of the phosphor coating material.

Furthermore, according to the present invention, there is further provided a phosphor substrate having the coating film.

Also, according to the present invention, there is further provided: a lighting device comprising: an insulating substrate; a coating film, provided on one side of the insulating substrate, formed by the phosphor coating; and a light-emitting element, provided on the coating the surface of the film on the opposite side of the insulating substrate. [Effect of invention]

With the phosphor coating material of the present invention, the phosphor layer can be easily provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, the same reference numerals are assigned to the same constituent elements, and descriptions thereof are appropriately omitted. All drawings are for illustrative purposes only. The shapes and size ratios of the components in the drawings do not necessarily correspond to the actual objects.

The expression "(meth)acrylic acid" in this specification represents a concept including both acrylic acid and methacrylic acid. Similar expressions such as "(meth)acrylate" are also the same. The term "phosphor particles" in this specification may mean "phosphor powder" which is an aggregate of phosphor particles depending on the context of the text. For example, "median diameter D ₅₀ of phosphor particles" described later is a value obtained based on the particle size distribution of phosphor powder of an aggregate of phosphor particles.

＜Phosphor paint＞ The phosphor coating material of this embodiment contains phosphor particles and a curable resin component. In the phosphor coating material of this embodiment, the content rate of phosphor particles is 25 vol % or more and 60 vol % or less in all non-volatile components.

The phosphor coating material of this embodiment contains a curable "resin component" instead of a glass binder. Therefore, when the phosphor coating material of this embodiment is used, it is not necessary to sinter at a high temperature, and the phosphor layer can be easily provided.

No need to sinter at high temperature means that the phosphors that can be used are not limited. Specifically, when it is desired to obtain a cured film with a glass adhesive, it is necessary to bake at a high temperature such as 600°C. When such high temperature is required, phosphors that can withstand high temperatures must be selected, and the available phosphors may be limited. In addition, peeling tends to occur when cooling from a high temperature. However, by preparing a phosphor coating material using a curable resin component, a phosphor layer that is not easily peeled off can be formed without requiring a high temperature such as 600°C. The absence of sintering at high temperature also means that there are few limitations in the heat resistance of the housing/substrate to which the paint is applied or printed, optimization of the expansion coefficient, etc.

In addition, by using the curable resin component, it is easy to form a suitably thin phosphor layer by coating or printing. This is particularly effective when the phosphor particle content in the phosphor coating material is high. In order to fully convert the light emitted by the light-emitting element into fluorescent light, and at the same time prevent the light emitted by the light-emitting element from directly passing through the phosphor layer, the inventors of the present invention combined phosphor particles in all non-volatile components of the phosphor coating. The content rate is set to 25 vol% or more.

By setting the phosphor particle content rate in the total nonvolatile components of the phosphor coating material to be 25 vol% or more, in addition to being able to sufficiently convert the light emitted by the light-emitting element into fluorescent light, other advantages can be achieved. An example of such an advantage is improvement in coating or printing suitability. By appropriately increasing the content rate of the fluorescent particles in the phosphor coating material, the flow of the phosphor coating material becomes moderately difficult, and it becomes easy to form a fluorescent layer with an appropriate film thickness.

In addition, there is also an advantage that cracks are less likely to occur in the phosphor layer by setting the phosphor particle content rate in the total non-volatile components of the phosphor coating material to 25 vol % or more. According to common knowledge, it is considered that one of the reasons for the occurrence of cracks is the difference in thermal expansion coefficient between the phosphor layer and the substrate on which the phosphor layer is provided. The curable resin component is relatively reduced by setting the phosphor particle content rate in the total nonvolatile components of the phosphor coating material to 25 vol % or more. Therefore, the difference in thermal expansion coefficient between the phosphor layer and the substrate on which the phosphor layer is provided becomes smaller. As a result, cracks hardly occur in the phosphor layer.

The phosphor particle content rate in the total nonvolatile components of the phosphor coating material is preferably 30 vol % or more, more preferably 35 vol % or more. Thereby, even when the phosphor layer is thin, the light emitted from the light-emitting element can be sufficiently converted into fluorescent light, and the color temperature of the light emitted from the light-emitting element can be greatly converted.

On the other hand, when the content rate of the phosphor particles in all the nonvolatile components of the phosphor coating material is too high, the phosphor particles tend to fall off from the formed phosphor layer. Therefore, the phosphor particle content rate in all nonvolatile components of the phosphor coating material is set to be 60 vol % or less.

Hereinafter, the components, physical properties, and the like contained in the phosphor coating material of the present embodiment will be described.

(phosphor particles) The phosphor coating material of this embodiment contains phosphor particles. The phosphor particles only need to be those that emit light by the light emitted from the light-emitting element. Depending on the desired color, color temperature, etc., only one type of specific phosphor particles may be used, or two or more kinds of phosphor particles may be used in combination.

Phosphor particles that can be cited include CASN-based phosphors, SCASN-based phosphors, La ₃ Si ₆ N ₁₁ -based phosphors, Sr ₂ Si ₅ N ₈ -based phosphors, Ba ₂ Si ₅ N ₈ One or more selected from the group consisting of phosphors, α-Sialon-based phosphors, β-Sialon-based phosphors, LuAG-based phosphors, and YAG-based phosphors . These phosphors usually contain activating elements such as Eu, Ce, and the like.

A CASN-based phosphor (a type of nitride phosphor) preferably contains Eu. The CASN-based phosphor is, for example, a red phosphor represented by the formula CaAlSiN ₃ : Eu ²⁺ , using Eu ²⁺ as an activator, and using a crystal composed of alkaline earth silicon nitride as a matrix. The definition of a CASN-based phosphor containing Eu in this specification does not include a SCASN-based phosphor containing Eu.

The SCASN-based phosphor (a type of nitride phosphor) preferably contains Eu. The SCASN-based phosphor is, for example, a red phosphor represented by the formula (Sr, Ca)AlSiN ₃ : Eu ²⁺ , using Eu ²⁺ as an activator, and using a crystal composed of alkaline earth silicon nitride as a matrix.

Specifically, the La ₃ Si ₆ N ₁₁ -based phosphor is La ₃ Si ₆ N ₁₁ :Ce phosphor. This is typically a wavelength conversion of blue light from a blue LED to yellow light.

Sr ₂ Si ₅ N ₈ -based phosphors are specifically Sr ₂ Si ₅ N ₈ :Eu ²⁺ phosphors and Sr ₂ Si ₅ N ₈ :Ce ³⁺ phosphors. These are typically wavelength-converted blue light from blue LEDs to yellow to red light.

Specifically, the Ba ₂ Si ₅ N ₈ phosphor is Ba ₂ Si ₅ N ₈ :Eu. These are typically wavelength-converted blue light from blue LEDs to orange to red light.

The α-Sialon-based phosphor preferably contains Eu. The α-Sialon containing Eu is, for example, represented by the general formula: M _x Eu _y Si _12-(m+n) Al _{(m+n) On} N _16-n . In the general formula, M is selected from the group consisting of Li, Mg, Ca, Y and lanthanide elements (but not including La and Ce), and at least one or more elements of Ca are included. When the valence of M is a, ax +2y=m, where x is 0<x≤1.5, 0.3≤m<4.5, and 0<n<2.25.

The β-Sialon-based phosphor preferably contains Eu. The β-Sialon containing Eu is represented by, for example, the general formula Si _6-z Al _z O _z N _8-z : Eu ²⁺ (0<Z≦4.2), and is represented by β-Sialon in which Eu ²⁺ is dissolved in a solid solution. composed of phosphors. In the general formula, the Z value and the europium content are not particularly limited. The Z value is, for example, 0 or more and 4.2 or less, and preferably 0.005 or more and 1.0 or less from the viewpoint of further improving the luminous intensity of β-Sialon. In addition, the content of europium is preferably 0.1 mass % or more and 2.0 mass % or less.

LuAG-based phosphors generally mean Lutetium aluminum garnet crystals. Considering the application in lighting devices, LuAG is preferably a LuAG:Ce phosphor. More specifically, LuAG can be represented by the composition formula of Lu ₃ Al ₅ O ₁₂ : Ce, but the composition of LuAG does not necessarily have to follow stoichiometry.

YAG-based phosphors generally refer to yttrium aluminum garnet crystals. Considering the application in lighting devices, YAG-based phosphors are preferably activated with Ce. More specifically, the YAG-based phosphor can be represented by the composition formula of Y ₃ Al ₅ O ₁₂ : Ce, but the composition of the YAG-based phosphor does not necessarily have to follow stoichiometry.

Commercially available products can be used as the phosphor particles. As commercially available phosphor particles, examples include ALONBRIGHT (registered trademark) of Denka Company Limited and the like. In addition, it can also be purchased from Mitsubishi Chemical Corporation or the like.

The median diameter _D50 of the phosphor particles is preferably 1 μm or more and 20 μm or less, and more preferably 5 μm or more and 15 μm or less. By appropriately adjusting the median diameter D ₅₀ , for example, the fluidity of the phosphor coating material can be adjusted, and a thin and uniform coating film can be easily formed.

In the particle size distribution curve of the phosphor particles, preferably two or more maxima are observed. Specifically, it is preferable that the maximum value is observed in both the region where the particle diameter is 1 μm or more and 6 μm or less and the region where the particle diameter is 10 μm or more and 25 μm or less. The observation of two or more maxima means that the phosphor particles contain both large particles and small particles. Since the small particles enter the "gap" between the large particles, it is easy to increase the content of the phosphor particles compared to the case of using only the large particles. In addition, even if the content rate of phosphor particles is increased, various physical properties as a coating material are easily maintained. In addition, when used as a coating film, the light emitted from the light-emitting element becomes less permeable.

The median diameter _D50 and particle size distribution curve of the phosphor particles can be appropriately pulverized by designing the modulation method of the phosphor particles, and appropriately mixing two or more phosphor particles with different particle sizes. etc. to be adjusted.

The particle size distribution curve of the phosphor particles can be measured with a laser diffraction/scattering particle size distribution analyzer after dispersing raw phosphor particles in a dispersion medium with an ultrasonic disperser. Next, the median diameter D ₅₀ can be obtained from the obtained particle size distribution curve. For details of the dispersion treatment and the measurement equipment, please refer to the examples described later. Incidentally, in this specification, the median diameter D ₅₀ and the particle size distribution curve are measured on a volume basis.

The phosphor coating material in this embodiment may contain only one type of phosphor particles, or may contain two or more types. As described above, the content rate of phosphor particles in all nonvolatile components of the phosphor coating material is 25 vol % or more and 60 vol % or less. The content is preferably 30 vol % or more and 60 vol % or less, more preferably 35 vol % or more and 60 vol % or less, and particularly preferably 40 vol % or more and 50 vol % or less.

(curable resin component) The phosphor coating material in this embodiment contains a curable resin component. In this specification, the "curable resin component" includes not only (1) a resin (polymer) component having a property of being cured by the action of heat, light, etc., but also (2) a monomer or The oligomer is a component that can be molecularized to form a resin (polymer) by the action of heat, light, etc. after the coating film is formed. In connection with the above, in this specification, in addition to polymers, monomers, or oligomers, polymerization initiators, curing agents, and the like are also regarded as part of the "curable resin component".

When the curable resin component contains resins, monomers or oligomers, these are usually organic substances. That is, the curable resin component usually contains an organic resin, an organic monomer, or an organic oligomer.

The curable resin component preferably contains a thermosetting resin component. Thereby, a high-durability lighting device can be manufactured. Of course, the curable resin component may contain a thermoplastic resin depending on the purpose and application.

The curable resin component preferably includes one or more selected from the group consisting of silicone resins and (meth)acrylate monomers. Among them, from the viewpoints of heat resistance, durability, and the like, silicone resins (resins having a siloxane bond as a main skeleton) are preferred.

The curable resin component preferably contains a silicone resin having a phenyl group and/or a methyl group. Such silicone resins are preferable in terms of compatibility with other components, solvent solubility, coatability, heat resistance, durability, and the like. The ratio of phenyl:methyl in this resin is, for example, about 0.3:1 to about 1.5:1.

The curable resin component may contain reactive groups. Thereby, the curable resin component itself can be hardened. In one example, the curable resin component preferably contains a silicone resin having a silanol group (-Si-OH). Thereby, the condensation reaction of the silanol group occurs at the time of coating film formation, and a cured coating film is obtained. The silanol content (OH weight %) of the silanol group (—Si—OH)-containing silicone resin is, for example, 0.1 mass % or more and 5 mass % or less. In another example, the curable resin component may be cured by the hydrosilylation reaction between the vinyl group-containing polymer and the Si-H group-containing silicone polymer (addition reaction type) .

The weight average molecular weight of the resin contained in the curable resin component is not particularly limited. Any weight-average molecular weight resin may be contained as long as it can form a coating film as a coating material. As an example, the weight average molecular weight of the resin contained in the curable resin component is usually 1,000 or more and 1,000,000 or less, preferably 1,000 or more and 500,000 or less. In the case of using a commercially available product as the resin contained in the curable resin component, catalog data can be used for the weight average molecular weight of the resin. When the weight average molecular weight cannot be known from a catalog or the like, it can be determined by, for example, gel permeation chromatography (GPC) measurement using polyethylene as a standard substance.

A commercial item can also be used for the resin contained in the curable resin component. Commercially available silicone resins can be obtained from, for example, Toray Dow Corning, Shin-Etsu Chemical Industries, and the like. Examples include RSN-0409, RSN-0431, RSN-0804, RSN-0805, RSN-0806, RSN-0808, RSN-0840 (manufactured by Toray & Dow Corning), KF-8010, X-22 -161A, KF-105, X-22-163A, X-22-169AS, KF-6001, KF-2200, X-22-164A, X-22-162C, X-22-167C, X-22-173BX etc. (manufactured by Shin-Etsu Chemical Industry Co., Ltd.).

As described above, the curable resin component may not contain a resin but may contain a monomer or an oligomer. For example, the curable resin component preferably contains a (meth)acrylate monomer. (Meth)acrylate monomers may be monofunctional or polyfunctional. The (meth)acrylate monomer preferably has two or more and six or less (meth)acrylic structures in one molecule.

The curable resin component preferably contains a monomer and an oligomer, and also contains a polymerization initiator. For example, when a curable resin component contains a (meth)acrylate monomer, it is preferable to use together with a radical polymerization initiator. The radical polymerization initiator is one that generates radicals by heat or active light.

As the curable resin component, in addition to the combination of the silicone resin, the (meth)acrylate monomer and the polymerization initiator as described above, any component known in the coating field may be used. The curable resin component may be, for example, (i) a urethane-based component containing a polyol and a polyisocyanate, (ii) an epoxy-based component, or the like.

As the polyol of (i), (meth)acrylic polyol, polyester polyol, polyether polyol, epoxy polyol, polyolefin-based polyol, fluorine-containing polyol, Polycaprolactone polyol, polycaprolactone polyol, polycarbonate polyol, etc.

As the polyisocyanate of (i), those having preferably 2 to 6 functional groups, more preferably those having 2 to 4 functional groups can be exemplified. Specifically, aliphatic diisocyanates, cyclic aliphatic diisocyanates, isocyanurate and biuret type adducts which are polymers of isocyanate compounds, adducts of isocyanate compounds added It is obtained from polyols or low molecular weight polyester resins, etc. As polyisocyanates, biuret type, isocyanurate type, adduct type, allophanate type and the like are known. These can also be used either.

The polyisocyanate of (i) may be a so-called blocked isocyanate. In other words, it may be in the form of a blocked isocyanate group in which a part or all of the isocyanate groups of the polyisocyanate are blocked by a protective group. For example, the isocyanate group is blocked with an active hydrogen compound such as alcohol-based, phenol-based, lactam-based, oxime-based, and active methylene-based compounds to form a blocked isocyanate group.

Commercially available products of polyisocyanates include, for example, DURANATE (trade name) series manufactured by Asahi Kasei Co., Ltd., TAKENATE (trade name) series manufactured by Mitsui Chemicals Co., Ltd., and Sumika Bayer Polyurethane Co., Ltd. DESMODUR (trade name) series manufactured by Bayer Urethane Co. Ltd., etc.

The (ii) epoxy-based curable resin component usually contains an epoxy resin and its curing agent. In the case of epoxy resins, examples are bisphenol A type epoxy resins, halogenated bisphenol A type epoxy resins, novolac type epoxy resins, polyethylene glycol type epoxy resins, bisphenol F type epoxy resins Resin, epoxidized oil, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, etc. The curing agent generally includes polyamines such as polyamines, amine adducts, and polyamides, and acid anhydrides.

The phosphor coating material of this embodiment may contain only one type of curable resin component, or may contain two or more types. The amount of the curable resin component in the phosphor coating material of the present embodiment is preferably 40 vol % or more and 65 vol % or less, particularly preferably 45 vol % or more and 60 vol % or less, in the total nonvolatile components.

(fluidity modifier) The phosphor coating material of this embodiment preferably contains a fluidity modifier. Thereby, the flow characteristics adjustment as a coating material, coating property adjustment, etc. can be performed.

As the fluidity regulator, silica particles such as hydrophobic silica and hydrophilic silica, alumina, and the like are suitably used. In particular, it is preferable to use fumed silica. Commercially available fluidity regulators include, for example, AEROSIL 130, AEROSIL 200, AEROSIL 300, AEROSIL R-972, AEROSIL R-812, AEROSIL R-812S, ArminiumOxideC (manufactured by Nippon Aerosil, AEROSIL is a registered trademark), Carplex FPS-1 (manufactured by DSL Corporation, trade name) and the like.

When the phosphor coating material of this embodiment contains a fluidity regulator, only one type of fluidity regulator may be contained, or two or more types of fluidity regulators may be contained. When the phosphor coating material of the present embodiment contains a flowability modifier, the amount thereof is 10 vol % or less, preferably 1 vol % or more and 5 vol % or less of the total nonvolatile components. In the case of a mass basis rather than a volume basis, the amount of the fluidity modifier is, for example, 5 mass % or less, preferably 0.1 mass % or more and 5 mass % or less in all nonvolatile components.

(solvent) The phosphor coating material of this embodiment preferably contains a solvent. Thereby, a phosphor coating material with good coatability can be obtained. The solvent includes water and/or organic solvent. As the organic solvent, a hydrocarbon-based solvent, a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, an amide-based solvent, an ether-based solvent, and the like can be exemplified.

A preferable organic solvent is, for example, an alcohol-based solvent. Specifically, methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol, tertiary butanol, etc. are mentioned, for example. In addition, preferable examples are ether bond-containing alcohols such as butyl carbitol (diethylene glycol monobutyl ether) and ethyl carbitol (diethylene glycol monoethyl ether). In particular, in the case of using a silicone resin as the resin, it is preferable from the viewpoint that the silicone resin can be dissolved/dispersed well to prepare a phosphor coating material having good coatability.

Furthermore, the solvent preferably contains an aromatic hydrocarbon solvent. In particular, when a silicone resin is used, it is possible to easily prepare a phosphor coating material with a good balance of various properties by using it in combination with an aromatic hydrocarbon solvent. As the aromatic hydrocarbon solvent, toluene, xylene and the like can be exemplified.

When using a solvent, only one type of solvent may be used, or two or more types of solvents may be used in combination. For example, the above-mentioned alcohol-based solvent and aromatic hydrocarbon solvent may be used in combination. When a solvent is used together, it is preferable that each solvent is present in an amount of at least 1 mass % of the total amount of the solvent, from the viewpoint of sufficiently obtaining the effect obtained by the combined use. When the phosphor coating material of the present embodiment contains a solvent, the amount of the solvent contained is preferably such that the concentration of the nonvolatile component is 90% by mass or less. However, the concentration of the nonvolatile components is not limited to this, and can be adjusted to an appropriate amount as long as a coating film can be formed.

(other ingredients) The phosphor coating material of this embodiment may contain components other than those described above. As far as other ingredients are concerned, there are, for example, anti-rust pigments, extenders, surface conditioners, waxes, defoamers, dispersants, UV absorbers, light stabilizers, antioxidants, levelers, plasticizers, charge control agents Wait.

(viscosity) The viscosity of the phosphor coating material of this embodiment is preferably adjusted appropriately. By adjusting the viscosity to an appropriate level, the improvement of coatability, the ease of forming a thin coating film, and the like are improved. Specifically, the viscosity of the phosphor coating is preferably 60 dPa·s or more and 500 dPa·s or less, more preferably 80 dPa·s or more and 400 dPa·s, as measured by a Brookfield viscometer at 25°C and 20 rpm. above. By adopting such a viscosity, the film-forming property at the time of forming a coating film by a screen printing method can be improved especially. In the case where the coating film is not formed by the screen printing method, the appropriate viscosity may be different from the above-mentioned numerical range.

(type of paint) The phosphor coating material of this embodiment may be a one-component type or a multi-component type of two or more components. Specifically, the resin composition for film formation of the present embodiment can be supplied as a one-liquid type composition in which all necessary components are uniformly mixed or dispersed. In addition, the resin composition for film formation of this embodiment may be supplied with a two-component type (two-component kit) in which a part of the components is the A liquid and the remaining component is the B liquid. From the viewpoint of storage stability before coating, a multi-liquid type phosphor coating material may be preferable. When the phosphor coating material of the present embodiment is a multi-liquid type, each liquid is uniformly mixed immediately before forming a coating film to obtain a coating material for coating. In this coating material for painting, the content rate of phosphor particles in all nonvolatile components is 25 vol % or more and 50 vol % or less.

<Coating film, phosphor substrate, lighting device> Using the above-mentioned phosphor coating material, a coating film containing phosphor particles can be formed. Furthermore, by using the above-mentioned phosphor coating material, a phosphor substrate having a coating film containing phosphor particles can be produced. In addition, using the above-mentioned phosphor coating material, it is possible to manufacture an insulating substrate, a coating film formed of the above-mentioned phosphor coating material provided on one side of the insulating substrate, and a coating film provided on the surface opposite to the insulating substrate on the coating film. Lighting devices of light-emitting elements (LED elements, etc.).

Hereinafter, the coating film, the phosphor substrate, and the lighting device will be described with reference to the illustration of the configuration example of the lighting device.

FIG. 1 is a schematic cross-sectional view of a lighting device. In the lighting device of FIG. 1 , the fluorescent coating film 26 is provided on the surface of the insulating substrate 20 in one direction. Between the insulating substrate 20 and the fluorescent coating film 26, from the insulating substrate 20 side, the first copper foil 22 and the white layer 24 are sequentially provided. A part of the first copper foil 22 is removed by etching to function as a copper circuit (copper wiring).

The surface mount type LED element 28 (light-emitting element) is provided on the surface of the fluorescent coating film 26 on the opposite side to the insulating substrate 20 . The surface mount type LED element 28 is electrically connected to the first copper foil 22 by a solder 30 provided so as to penetrate the white layer 24 and the fluorescent coating film 26 . The surface mount type LED element 28 is made to emit light by supplying power to the surface mount type LED element 28 through the first copper foil 22 and the solder 30 . From the viewpoint of improving the luminous efficiency of the phosphor paint, it is preferable to provide the white layer 32 (more specifically, the white resin layer 32 ) below the surface mount type LED element 28 . Thereby, light transmission (transmission) can be prevented. Furthermore, at the interface between the white layer 32 and the fluorescent coating film 26, at least a portion of the incident light from the fluorescent coating film 26 is reflected. The lighting device of FIG. 1 may include a plurality of surface mount LED elements 28 .

The second copper foil 22B may be provided on the surface in the other direction of the insulating substrate 20 (the surface on the opposite side from the side where the fluorescent coating film 26 is provided). By having the first copper foil 22 on one surface of the insulating substrate 20 and the second copper foil 22B on the other surface, the force balance on both surfaces of the insulating substrate 20 can be achieved, and the occurrence of warpage, for example, can be suppressed.

The material of the insulating substrate 20 is not particularly limited as long as it can be used for a PWB (printed circuit board). For example, polyimide resin, silicone resin, (meth)acrylic resin, urea resin, epoxy resin, fluororesin, glass, metal (aluminum, copper, iron, stainless steel, etc.) and the like can be used. Preferably, from the viewpoint of heat resistance, polyimide resin, silicone resin, glass, metal (a so-called "metal substrate" using aluminum or copper as a base metal and providing an insulating layer, etc.) can be used. It is better to use a material sold under the name of "bonding sheet" in the market. The thickness of the insulating substrate 20 is not particularly limited as long as it can be used in a lighting device. For example, it is 50 μm or more and 1000 μm or less, and specifically, 50 μm or more and 500 μm or less.

The white layer 24 and the white layer 32 can be provided with, for example, white paint. The composition and properties of the white paint are not particularly limited as long as the white layer 24 can be formed. Examples of the above-mentioned coating composition include a coating composition in which a white pigment is used instead of phosphor particles. The coating method may be the same as the fluorescent coating film 26 described below. As a white pigment, known pigments, such as titanium oxide, can be mentioned as an example. From the viewpoint of stability and the like, inorganic pigments are preferred. The thickness of the white layer 24 is, for example, 10 μm or more and 500 μm or less, and specifically, 20 μm or more and 400 μm or less.

The fluorescent coating film 26 can be provided by applying the above-mentioned coating composition. By means of the fluorescent coating film 26, the light emitted from the light emitting element is converted into light having different wavelengths/color temperatures. The coating method is not particularly limited. For example, the coating composition can be applied using various coaters known in the coating art. Alternatively, the coating composition may be applied by a printing method such as a screen printing method. After coating, drying treatment and hardening treatment are preferably performed. The conditions of the drying treatment are, for example, 60° C. or higher and 100° C. or lower, and 15 minutes or longer and 60 minutes or shorter. The conditions of the hardening treatment are, for example, 100° C. or more and 200° C. or less, and 30 minutes or more and 240 minutes or less.

The coating amount of the coating composition is adjusted so that the thickness of the fluorescent coating film 26 in the lighting device as a finished product is preferably 150 μm or less, more preferably 30 μm or more and 100 μm or less, particularly preferably 30 μm or more and 80 μm or less . Since the content rate of the phosphor particles in the coating composition is 25 vol% or more, preferably 30 vol% or more, more preferably 35 vol% or more, even if the thickness of the fluorescent coating film 26 is 150 μm or less, the surface mount type can be used. The light emitted by the LED element 28 is sufficiently converted into fluorescent light, and the light emitted by the surface-mounted LED element 28 cannot easily pass through the fluorescent layer directly.

In addition, the hardened white layer 24 and/or the fluorescent coating film 26 may be drilled by machining to provide a hole through which the solder 30 passes. About the part where the surface mount type LED element 28 (light-emitting element) and the 1st copper foil 22 are connected by the solder 30 after that, a known method can be suitably applied.

As for the surface mount type LED element 28 (light emitting element), CSP, SMD (Surface Mount Device, surface mount element), flip chip element and the like can be exemplified. In this embodiment, the light-emitting element is preferably a CSP. Furthermore, the light-emitting element typically emits blue light.

In this embodiment, it is particularly preferable that the light-emitting element does not have a reflection portion. Specifically, as shown in FIG. 2A , a conventional surface-mounted LED element (light-emitting element) is provided with a reflecting portion so that light from the LED chip does not leak laterally and downwardly. However, in this embodiment, as shown in FIG. 2B , it is preferable that the surface mount type LED element 28 (light-emitting element) does not have a reflecting portion. By using a light-emitting element without a reflective portion, light from the LED chip leaks laterally or downwardly. Next, the leaked light irradiates the part indicated by α of the fluorescent coating film 26, so that the part α emits light. Thereby, the problems of glare and multiple shadows are further reduced.

In the light-emitting element of FIG. 2A , the semiconductor light-emitting element 100 is arranged in a package-like portion 108 formed by the substrate 102 and the reflection portion (case) 104 , and the package-like portion 108 is filled with a sealing member 110 (translucent resin). ). The substrate 102 may have wirings 112 . In Fig. 2B, the same elements as in Fig. 2A are given the same symbols. In the light-emitting element of FIG. 2B , the case (reflector) is not used. After the semiconductor light emitting element 100 is mounted as shown, the sealing member 110 may be formed by molding using a desired mold. Alternatively, the sealing member 110 preliminarily formed into a desired shape is prepared and adhered to the substrate 102 so as to cover the semiconductor light emitting element 100 .

The embodiments of the present invention have been described above, but these are merely examples of the present invention, and various structures other than those described above may be employed. In addition, this invention is not limited to the above-mentioned embodiment, The deformation|transformation, improvement, etc. within the range which can achieve the objective of this invention are also included in this invention. [Example]

Hereinafter, embodiments of the present invention will be described in detail based on Examples and Comparative Examples. For the sake of prudence, it is specifically stated that the present invention is not limited to the embodiments only.

<Material> Prepare as follows. (Phosphor particles) ・CASN-1: CASN-based phosphor manufactured by Denka Corporation, product number RE-650YMDB, D ₅₀ =15.7μm ・CASN-2: CASN-based phosphor manufactured by Denka Corporation, product number RE -Sample 650SD4, _D50 =3.2μm

The particle size distribution (D ₅₀ ) of the phosphor particles was measured as follows. (1) Dispersion treatment by ultrasonic The dispersion obtained by uniformly dispersing 30 mg of phosphor particles in 100 mL of an aqueous solution of sodium hexametaphosphate adjusted to 0.2% by mass was placed in a cylindrical container with a bottom radius of 2.75 cm . Next, a cylindrical tip with a radius of 10 mm of an ultrasonic homogenizer (manufactured by Nippon Seiki Co., Ltd., US-150E) was immersed in the dispersion for 1.0 cm or more, and ultrasonic waves were irradiated at a frequency of 19.5 kHSz and an output power of 150 W. 3 minutes. (2) Measurement of particle size distribution The dispersion liquid prepared in (1) above was measured using a laser diffraction/scattering particle size distribution analyzer (manufactured by Microtrac Bell, MT3300EXII) to obtain particle size distribution. In addition, _D50 was calculated|required from the data of particle size distribution.

(Curable resin component) Toray Dow Corning's silicone resin "RSN-0805" (containing silanol group, silanol group content (OH weight) 1%, silica content 48% by weight, phenyl: methyl Ratio=1.1:1, weight average molecular weight 200~300×10 ³ , containing xylene, resin solid content 50% by weight)

(fluidity modifier) Nippon Aerosil's fumed silica AEROSIL 200

(solvent) Butyl Carbitol

(Preparation of paint composition) Of the ingredients listed in the table below, the curable resin ingredient (silicone resin) and the solvent are first mixed to obtain a homogeneous solution. Then, phosphor particles and a fluidity modifier (Example 3 only) were added to this solution, and uniformly mixed and dispersed to obtain a coating composition. The viscosity of the obtained coating composition was measured using the No. 4 rotor of the B-type viscometer at 25° C. and 20 rpm rotation speed.

<Formation of coating film (phosphor layer)/production of lighting device> Using the above-prepared paint composition and the like, a lighting device having the structure described in FIG. 1 was produced (a plurality of CSPs are arranged on the phosphor layer at a constant interval). The process steps are briefly shown below. (1) Prepare the adhesive sheet CS-3305A made by Lee Chang Industrial Co., Ltd. with double-sided bonded copper foil as the insulating substrate material. Its copper foil is etched to form a copper circuit on the first copper foil. (2) A white layer with a thickness of 40 μm was formed on the first copper foil with a white paint (a product obtained by kneading titanium oxide/aluminum with a silicon-oxygen binder at 50 vol%). (3) The above phosphor coating was screen-printed (film formation) on the white layer using an 86-mesh screen, pre-cured at 80°C for 30 minutes, and post-cured at 180°C (main curing) for 60 minutes minute. Thereby, a phosphor layer is formed. The thickness of the phosphor layer at this time was aimed at 50 μm. (4) The white layer and part of the phosphor layer are drilled to provide holes for solder. Next, a commercially available CSP (WICOP SZ8-Y15-WW-C8, manufactured by Seoul Semiconductor Co., Ltd., non-reflection product, color temperature 2200-2300K) which is a surface mount type LED element and the first copper foil (copper circuit) were mixed with Solder for electrical connection.

<Evaluation: Printability> In the above (3), when a phosphor layer with a thickness of 45 to 55 μm could be formed, the printability was good (◯), and when a phosphor layer with a sufficient thickness could not be formed, the printability was poor (×).

<Evaluation: Appearance of the phosphor layer> The appearance of the phosphor layer formed in the above (3) was observed. In Table 2 below, when no abnormality that may be a problem in actual use is found, it is recorded as "no abnormality", and when an abnormality that may be a problem in actual use is found, the content of the abnormality is recorded.

<Evaluation: Durability of the phosphor layer, etc.> The tests of the items in Table 1 below were carried out for those having "no abnormality" in the evaluation of the appearance of the phosphor layer described above. Those who meet the eligibility criteria of all items in Table 1 are recorded as "Passed" in Table 2.

〔Table 1〕 project method Eligibility criteria stickiness Using a sharp knife, 100 squares up to the insulating substrate were drawn at intervals of 1 mm, scotch tape was attached to the surface, and it was peeled off at once. No peeling. hardness According to JIS K5600-5-4 3H Solvent After immersing in isopropyl alcohol for 5 minutes at room temperature, scotch tape was attached and peeled off at one go. There is no abnormal phenomenon such as swelling and peeling of the coating film. Acid resistance After immersing in 10% sulfuric acid for 30 minutes at room temperature, a scotch tape was attached and peeled off at once. There is no abnormal phenomenon such as swelling and peeling of the coating film. Alkali resistance After immersing in 5% sodium hydroxide for 5 minutes at room temperature, scotch tape was attached and peeled off at once. There is no abnormal phenomenon such as swelling and peeling of the coating film. Solder heat resistance After being immersed in a solder bath at 260°C for 20 seconds, the appearance of the coating film was confirmed. There is no abnormal phenomenon such as swelling and peeling of the coating film. PCT (Pressure Cooker Test) After 9 hours at a temperature of 121° C. and an air pressure of 0.2 MPa, the transparent tape was attached and peeled off at one go. There is no abnormal phenomenon such as swelling and peeling of the coating film. Hot and cold cycle After performing 1000 cycles of cooling and heating cycles (30 minutes at -40°C → 30 minutes at 125°C) as one cycle, the above-mentioned evaluation of "adhesion" was performed. No peeling. heat resistance After 1000 hours at 150°C, the evaluation of the above-mentioned "tackiness" was performed. No peeling.

<Evaluation: Conversion of color temperature> Current flows through the lighting device fabricated in the above-described manner, causing the lighting device to emit light. The color temperature of the light emitted from the lighting device was measured using an all-beam measurement system (device having an integrating sphere) manufactured by Otsuka Electronics Co., Ltd. When the measured color temperature is 2000 to 2100K and the color temperature conversion of at least 100K or more occurs from the color temperature of the CSP itself (2200 to 2300K), the color temperature conversion property is evaluated as good "○". In addition, in Comparative Examples 1 and 2 in which the properties of the phosphor layer were abnormal, this evaluation was not performed.

The composition, evaluation results, etc. of the phosphor paint are summarized in the following table.

〔Table 2〕 Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Phosphor particles CASN-1 (large particle size D ₅₀ =16µm) 50vol% of all non-volatile components - 48.1vol% in all non-volatile components 35vol% of all non-volatile components 20vol% of all non-volatile components 65vol% of all non-volatile components Phosphor particles CASN-2 (small particle size D ₅₀ =5µm) - 50vol% of all non-volatile components 12vol% of all non-volatile components - - - Curable Resin Component Silicone Resin 50vol% of all non-volatile components 50vol% of all non-volatile components 38.8vol% in all non-volatile components 50vol% of all non-volatile components 80vol% of all non-volatile components 35vol% of all non-volatile components fluidity modifier - - 0.84 parts by mass relative to 100 parts by mass of phosphor particles and curable resin components - - - solvent 20 parts by mass with respect to 100 parts by mass of all nonvolatile components 20 parts by mass with respect to 100 parts by mass of all nonvolatile components 14 parts by mass relative to 100 parts by mass of phosphor particles and curable resin components 20 parts by mass with respect to 100 parts by mass of all nonvolatile components 20 parts by mass with respect to 100 parts by mass of all nonvolatile components 20 parts by mass with respect to 100 parts by mass of all nonvolatile components Viscosity (dPa s) 100 300 150 80 50 150 Evaluation: Printability ○ ○ ○ ○ × ○ Evaluation: Membrane Properties nothing unusual nothing unusual nothing unusual nothing unusual Cracking occurs Phosphor detachment from phosphor film Evaluation: Durability of the phosphor layer qualified qualified qualified qualified - - Evaluation: Component color temperature (K) ○ ○ ○ ○ - -

Since a phosphor coating containing phosphor particles and a curable resin component is used, and the content rate of phosphor particles in all non-volatile components is 25 vol% or more and 60 vol% or less, it is not necessary to bond such as glass. It can be sintered at a high temperature like an agent, but can be processed at a relatively low temperature of about 180°C to form a phosphor layer. In addition, the appearance and durability of the formed phosphor layer were good. In addition, the color temperature of the light emitted from the CSP is largely converted by the formed phosphor layer.

This application claims priority based on Japanese Invention Patent Application No. 2020-134386 filed on August 7, 2020, and incorporates the entire disclosure content of this Japanese invention patent application into the disclosure content of this case.

20: Insulating substrate 22: The first copper foil 22B: Second copper foil 24: white layer 26: Fluorescent coating 28: Surface Mount LED Components 30: Solder 32: White layer (white resin layer) 100: Semiconductor light-emitting element 102: Substrate 104: Reflector (shell) 108: Package like part 110: Sealing member 112: Wiring

[ Fig. 1 ] is a schematic cross-sectional view of the lighting device. [FIG. 2] A and B are diagrams for explaining an LED chip without a reflective portion and an LED chip with a reflective portion.

20: Insulating substrate

22: The first copper foil

22B: Second copper foil

24: white layer

26: Fluorescent coating

28: Surface Mount LED Components

30: Solder

32: White layer (white resin layer)

Claims (19)

A phosphor coating material includes phosphor particles and a curable resin component, and the content rate of the phosphor particles in all nonvolatile components is 25 vol % or more and 60 vol % or less. The phosphor coating of claim 1, wherein the curable resin component includes a thermosetting resin component. The phosphor coating of claim 1 or 2, wherein the curable resin component comprises silicone resin. The phosphor coating of claim 1 or 2, wherein the curable resin component comprises a silicone resin having a phenyl group and a methyl group. The phosphor coating of claim 1 or 2, wherein the curable resin component comprises a silicone resin having a silanol group. The phosphor coating material according to claim 1 or 2, wherein the median diameter D ₅₀ of the phosphor particles is 1 μm or more and 20 μm or less. The phosphor coating material according to claim 1 or 2, wherein two or more maxima are observed in the particle size distribution curve of the phosphor particles. The phosphor coating material according to claim 7, wherein in the particle size distribution curve of the phosphor particles, a maximum value is observed in both a region with a particle size of 1 μm or more and 6 μm or less and a region with a particle size of 10 μm or more and 25 μm or less . The phosphor coating according to claim 1 or 2, wherein the phosphor particles comprise phosphors from CASN-based phosphors, SCASN-based phosphors, La ₃ Si ₆ N ₁₁ -based phosphors, Sr ₂ Si ₅ N ₈ It is composed of phosphors, Ba ₂ Si ₅ N ₈ phosphors, α-Sialon phosphors, β-Sialon phosphors, LuAG phosphors and YAG phosphors One or two or more selected from the group. The phosphor coating according to claim 1 or 2, further comprising a fluidity modifier. The phosphor coating of claim 1 or 2, further comprising a solvent. The phosphor coating material of claim 11, wherein the solvent comprises an aromatic hydrocarbon solvent. The phosphor coating according to claim 1 or 2, wherein the viscosity measured by using the B-type viscosity agent at 25° C. and 20 rpm rotation speed is above 60 dPa·s and below 500 dPa·s. A coating film formed from the phosphor coating according to any one of claims 1 to 13. According to the coating film of claim 14, its thickness is below 150 μm. A phosphor substrate having the coating film of claim 14 or 15. A lighting device, comprising: an insulating substrate; a coating film, provided on one side of the insulating substrate, formed by the phosphor coating material of any one of claims 1 to 13; and a light-emitting element, provided on the coating film on the opposite side of the insulating substrate. The lighting device of claim 17 is provided with a plurality of the light-emitting elements. The lighting device of claim 17 or 18, wherein the light-emitting element does not have a reflecting portion.

Images